ABSTRACT
Keratoprosthesis (Kpro) forms the last resort for bilateral end-stage corneal blindness. The Boston Type 1 and 2 Kpros, the modified osteo-odonto Kpro and the osteo-Kpro are the more frequently and commonly performed Kpros, and this review attempts to compile the current data available on these Kpros worldwide from large single-center studies and compare the indications and outcomes with Kpros in the Indian scenario. Although the indications have significantly expanded over the years and the complications have reduced with modifications in design and postoperative regimen, these are procedures that require an exclusive setup, and a commitment toward long-term follow-up and post-Kpro care. The last decade has seen a surge in the number of Kpro procedures performed worldwide as well as in India. There is a growing need in our country among ophthalmologists to be aware of the indications for Kpro to facilitate appropriate referral as well as of the procedure to enable basic evaluation during follow-ups in case the need arises, and among corneal specialists interested to pursue the field of Kpros in understanding the nuances of these surgeries and to make a judicious decision regarding patient and Kpro selection and more importantly deferral.
ABSTRACT
This paper presents the results of an investigation on the distribution of 210Po in Mutharasanallur pond ecosystem. It has been demonstrated that 210Po is non-uniformly distributed within the ecosystem. The results of the study show a dissolved 210Po concentration in pond water of 1 4mBq l–1 . The sediment samplso recorded a 210Po activity of 59 9 Bq kg–1. The aquatic organisms showed differential accumulation of the radionuclide with enhanced bioaccumulation in soft tissues and muscle. The 210Po activity in the biota fell within the range of 1·2 —53 3 Bq kg-1 (wet wt). The bivalve mussel, Lamellidens marginalis was identified to accumulate higher concentration of 210Po in soft tissues, suggesting that these organisms could serve as a bio-monitor of 210Po radionuclide in a freshwater system. The concentration factors of 210Po for the biotic components ranged from ~ 102— ~104 . Analyses of the results indicate that prawn and fish represent an important source of supply of 210Po to humans via dietary intake. Results of210Po activity in the abiotic and biotic components of the pond ecosystem were higher when compared with those of Cauvery river system, the primary water source of the pond.
ABSTRACT
We studied the natural radioactivity distribution of an α-emitting radionuclide, 226Ra in water, sediment and biota (plankton, weed, snail, bivalve, prawn and fish) of Cauvery river ecosystem extending a stretch of 95 km. The dissolved 226Ra concentration in river water ranged from 0·82mBq.I-1 to l 06mBq.l-1 (mean: 0·93mBq.l-1) and the activity in river sediments from 4·7Bq.kg-1 to 6·9Bq.Kg-1 (mean: 5·6Bq.kgg-1 dry wt.). The 226Ra activity levels in the biota were within a narrow range from below detection limit to 3·80 Bq.kg-1 (wet wt). Generally higher 226Ra concentrations are observed in the shells and bones of aquatic organisms than in their tissues and muscles. The concentration factors (CFs) of 226Ra for the biotic components ranged from ~ 101 to ~ 103. The significance of 226Ra activity in the abiotic and biotic components of Cauvery river are discussed.